Res ipsa loquitur allows a judge or jury to infer that the defendant's negligence was, more likely than not, the cause of the plaintiff's harm.

Res ipsa loquitur is a legal doctrine that allows a judge or jury to infer negligence on the part of the defendant if the accident that caused the plaintiff's harm is the kind that typically does not happen without negligence, the evidence rules out the possibility that the harm was caused by the plaintiff or third parties, and the defendant had exclusive control over the thing that caused the harm.